Estudo e Aperfeiçoamento do Vocoder de Transformada Senoidal

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The basic sinusoidal analysis/synthesis system is presented and recent parameters codification techniques are studied. In addition, new methods for improving the speech quality of Sinusoidal Transform Vocoders at 2,4 and 4,8 Kbps are presented. One of them is a refinement in the pitch estimation, since pitch accuracy is essential for the efficiency of the harmonic sine-wave speech model. Another proposal is a more efficient procedure for estimation of the spectral envelope parameters, which exploits the subjective loudness psychoacoustic characteristic of the human hearing system. This technique reduces the amount of envelopes parameters with no reduction in the speech quality. An alternative approach for the synthetic phase composition is also proposed, so that a better computational cost is obtained. Experimental results indicate that the use of all these methods in combination with the basic sinusoidal analysis/synthesis system enhances the performance of a Sinusoidal Transform Vocoder operating at 2,4 and 4,8 kbps, improving its quality and computational cost.

ASSUNTO(S)

codificação senoidal harmonic model sine-wave model modelo harmônico telecomunicacoes sinusoidal coding sinusoidal excitation excitação senoidal modelo senoidal

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